You can't be a decent evil twin without bushy, severely slanted eyebrows, and a nice pointy goatee. But why do we read these features as so very diabolical? A study explains that it all has to do with the geometry of evil.

Dr Derrick Watson and Dr Elisabeth Blagrove of the Unversity of Warwick have apparently grown up watching the same cartoons that I have. Anyone worth their salt knows that the evil twin has a pointy beard — or, at the very least, dark eyebrows that were slanted in a way that made them look angry. Usually the twin does things like rubbing their hands together and cackling evilly, to remove all doubt, but that's just for the people who can't pick up on visual cues. Why are the goatee and the severe eyebrows such a universal code for evil?

The researchers think that those features give a face a shape more like a downward pointing triangle. People seem to find the shape itself threatening. Volunteers in a study were asked to look at pictures of positive, neutral, and negative faces. They detected the angry faces first. This makes sense. If someone near you is troubled, you want to look them over as quickly as possible to make sure everything's okay.

The volunteers were then asked to look at pictures of triangles. Triangles were shown pointing up, down, to the left, and to the right. The subjects looked at the downward facing triangles as quickly as they looked at the negative faces. Something about that shape — the downward facing triangle — reminds people of an angry or negative face. So when people paint or pluck their eyebrows into a shape that suggests a downward facing triangle, and grow a goatee, which makes their chin look pointier, their face takes on a negative expression, no matter what their actual features do. Why downward facing triangles caused the subjects such anxiety is anyone's guess though. Maybe the next experiment should involve drawing a goatee on the triangles?